Utilization of electronic package assemblies for the purpose of electrically coupling various circuit devices is, of course, well known, with various examples being shown and described in the following patents:
U.S. Pat. No. 4,830,623-M. J. Owens PA1 U.S. Pat. No. 5,059,129-W. L. Brodsky et al. PA1 U.S. Pat. No. 5,176,524-H. Mizuno
In the design of electronic package assemblies wherein direct contact is desired between the individual electrical conductors (e.g., printed circuit lines, contact pads, etc.) which constitute part of the circuit devices being coupled, precise alignment between the conductors as well as application of a reliable contact pressure of sufficient duration and capable of withstanding possible adverse environmental conditions (e.g., heat, moisture) are considered essential. Clearly, alignment, particularly when involving high density, extremely small conductors, is deemed critical to effective package assembly and operation. Concerning force application, it is also known that excessive pressure can result in damage to various components of the assembly (particularly the conductors) during both assembly and/or operation. Additionally, the provision of such pressure has heretofore typically been accomplished through the utilization of relatively large and complex components (e.g., connector housings) needed to produce these assemblies, thus also adding unnecessarily to the cost thereof. In those assemblies subjected to adverse environmental conditions such as mentioned above, failure to withstand same has also resulted in such problems as contact corrosion, reduced contact pressure, increased maintenance costs, etc.
In U.S. Pat. No. 4,902,234 (W. L. Brodsky et al.), assigned to the same assignee as the instant invention, there is defined a connector assembly wherein an elastomeric pressure exertion member is utilized to provide reliable contact pressure against at least one of the circuit members (e.g., a flexible circuit). This exertion member includes a base plate, a plurality of individual compressible elements located on one side of the plate, and a resilient member located on the plate's other side. As understood from the following, some of the advantageous teachings of this patent may be successfully utilized in the present invention. The disclosure of U.S. Pat. No. 4,902,234 is thus incorporated herein by reference.
One example of an electronic package to which the teachings herein particularly apply is often referred to in the art as a multichip module (MCM) wherein several semiconductor devices (chips) are used in combination with a common substrate (e.g., ceramic). The chips are typically positioned on the substrate's upper surface and electrically coupled, including possibly to one another, to associated circuitry also typically located on the same surface. One technique developed by the assignee of the present invention for this purpose is a solder process known as controlled collapse chip connection (C4).
Understandably, the growing demand for increased miniaturization of such packages necessitates an effective means for electrically coupling the package to various external circuits (e.g., on a larger substrate such as a printed circuit board on which the package is positioned), while also assuring effective positioning thereof within a suitable, protective housing.
As will be defined hereinbelow, the electronic package assembly of the present invention defines a miniaturized compact package structure that uniquely provides effective, reliable contact pressure of relatively low magnitude between the two circuitized substrates therein through the utilization of effective materials which are relatively inexpensive and which can withstand adverse environmental conditions such as excessive heat and moisture, while also assuring effective, aligned positioning of the substrates and the various components (e.g., chips) thereof. It is believed that such an electronic package, including a connector assembly for use therewith, would constitute a significant advancement in the art.